1. Field
The invention is in the field of blast hole stemming and of machines therefor.
2. State of the Art
It is presently common practice in open pit mining to break up material in the pit by a series of blasting operations, so that overburden can be removed and dumped as waste and ore can be removed and transported to a mill for processing. The blasting procedure normally involves drilling boreholes downwardly from substantially horizontal surfaces in the pit. The drill cuttings will pile up concentrically about such a borehole as it is drilled. An explosive charge is placed in the bottom of the resulting borehole, with a blasting cord extending therefrom up to the surface for detonating the charge. With the charge thus in place, the borehole is stemmed, i.e. is filled with the drill cuttings. Normally, this is accomplished manually by a crew of four or five men with hand shovels.